%%
%% The LaTeX Companion, 3ed
%%
%% Example 8-1-8 on page I-583 in "The \protect \nxLcs  {includegraphics} syntax in the graphicx package".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{207.0pt}
\newcommand\HR{\rule{1em}{0.4pt}}
\newcommand\bluefbox[1]{\textcolor{blue}{\setlength\fboxsep{0pt}%
                                      \fbox{\textcolor{black}{#1}}}}
%StartShownPreambleCommands
\usepackage{graphicx,color}
% \bluefbox and \HR as before
%StopShownPreambleCommands

\begin{document}
L\HR\bluefbox{\includegraphics
                [viewport=20 20 50 80]
                {latex-logo.pdf}}%
\HR middle\HR
\bluefbox{\includegraphics
            [trim= 20 20 0 -30,clip]
            {latex-logo.pdf}}%
\HR R
\end{document}
